Director firing system



E. P. ROSS- in AL DIRECTOR FIRING SYSTEM Oct. 12, 194

Filed March 31, 1932 2 Sheets-Sheet 1 INVENTORS ElliottP. Ross Y Hzrry .S. Marsh fl /f 4.45m,

ATTORNEYS '2 Sheets-Sheet 2 Filed March 31, 1952 INVENTORS Elliott H Ross By Harry S. Marsh ATTORNEYS Patented Oct. 12, 1 948 DIRECTOR FIRING SYSTEM Elliott P. Ross, Forest Hills, and Harry S. Marsh,

Great Neck, N. Y., assignors, by mesne assignments, to Ford Instrument Company, Inc, Long Island City, N. Y., a corporation of New York Application March 31, 1932, Serial No. 602,373

1 Renewed February 25, 1935 18 Claims.

This invention relates ingeneral to director or salvo firing systems for ordnance and in particular to a firing mechanism to be used with such systems for firing ordnance mounted on a ship or other angularly moving platform.

In salvo firing, all of the guns of a battery are fired simultaneously at a predetermined point in the roll of the ship. This is frequently accomplished by the use of afiring mechanism which can be set to close the firing circuit at a predetermined point in the ships roll and which is provided with means for closing the firing circuit when this predetermined point in the ships roll is reached; Due to the fact that there is an appreciable lapse of time between the instant the firing circuit is closed and the instant the projectile leaves the guns muzzle and that during this time the gun is carried out or the position it occupied at the instant the, firing circuit was closed, the firing circuit must be closed at apoint in the ships roll in advance of the point. at which the projectile must leave the gun, in order to hit the target.

It has been proposed to take care of this advance time interval by so proportioning the parts of the firing mechanism that the circuit "will be closed at a fixed angular distance in advance of the position in the roll of the ship at which the projectile should leave the guns muzzle in order that it hit the target. As the speed of roll of the Ship is different at every point in the roll this expedient will at best give a correct advance time interval at but one point in the roll and at all other points will give an advanc time interval which is either too great or too small.

A firing mechanism has also been proposed which maintains the advance time interval at a constant and proper value atall points in the roll of the ship by varying, in accordance with the velocity of the roll of the ship, the angular distance by which the closingof the firing circuit is advanced. This is accomplishedby the use of a, gyrcscopic means to advance the closing point of the firing circuit in proportion to the velocity .of the roll, which gyroscopic means is separate from and in addition to the gyroscopic means used to move the firing circuit closing member relative to the ship. The additional gyroscopic means renders the mechanism more delicate and introduces a source of error which may at times be greater than the error which itis intended to correct, for in order to obtain the desired results it will be necessary to maintain two gyroscopes leve1by compensating for the effect of stray producing influences to which they are subject.

This invention isin the nature of an improvement over the above mentioned firing mecha-. nisms and has for an object a firing mechanism of simple, rugged construction having a minimum of delicate, adjustable parts, in which a single gyroscope is used to move the firing circuit closing member relative to the ship as the Ship rolls and to advance the point of closing of the firing circuit proportional to the velocity of roll of the ship.

In accordance with the invention the firing mechanism comprises a single gyroscopic unit and follow-up mechanism therefor which operates suitable mechanism for continuously determining the level angle, that is, the angle which the ships deck makes with the horizontal in the plane of the line of sight, and the velocity of roll of the ship, The value of the level angle is continuously applied to an input member of a computing device which has another input member operatively connected to the output member of a second computing device whereat the director correction, that is, the angle which the ships deck must make with the horizontal in the plane of the line of sight at the tim the projectile leaves the guns muzzle in order to hit the target,

is computed from the arbitrary gun elevation, that is, the gun elevation arbitrarily chosen by the operator who determines the point in the ships roll at which the projectile is to leave the guns muzzle, corrected for cross roll if desired, and the sight depression, that is, the angle the gun must make with the horizontal at the time the projectile leaves the guns muzzle in order to hit the target.

The computing device first mentioned serves to continuously subtract the level angle from the director correction and operates from its output a, firing switch in accordance with this difference. The switch is so arranged that, with zero correction for advance time interval, it will closethe firing circuit when the level angle is equal to the director correction. To take care of the advance time interval due to the velocity of roll, the switch is provided with a device operatively connected to the mechanism for continuously determining the velocity of roll, which continuously adjusts the firing switch so that the firing circuit willbe closed at an angular distance in advance of the point in the roll of the ship at which the shell is to leave the guns muzzle, proportional to the velocity of the roll. By this arrangement the advance time interval is constant for all points in the roll. The firing switch adjusting device is so 3 arranged that if it is desired it may be locked in any position of adjustment.

The particular nature of the invention as well as other objects and advantages thereof will appear most clearly from a description of a preferred embodiment thereof as shown in the accompanying drawings, in which,

Fig. 1 is a schematic representation of the entire firing mechanism, the firing switch being shown in sufficient detail to bring out its novel construction;

Fig. 2 is a part sectional end view of the circuit closing switch of Fig. l with the parts thereof arranged in the firing circuit closing position; and

Fig. 3 is a view similar to that of Fig. 2 but shows the parts of the switch in an open circuit position.

When using the firing mechanism illustrated in Fig. 1 of the drawings to fire guns mounted on a ship or other moving platform, the sight depression and the arbitrary gun elevation angle, corrected for cross-level if desired, are transmitted by means not shown, to the operator in charge of the firing mechanism. The operator will turn hand crank I mounted on shaft 2 until the value of the gun elevation angle is indicated on dial 3 opposite fixed index 4, dial 3 being connected to shaft 2 through gear 5. The rotation of shaft 2 is transmitted through'gears 6 and i to side 8 of a differential 8, and since side 8" can at this time be considered as fixed, center 8, and shaft 9 upon which it is fixed will be rotated in accordance with the input at crank i. The operator will then turn crank it], mounted on shaft II until the value of the sight depression is indicated on dial l2 opposite fixed pointer l3, dial l2 being connected to shaft ll through gear id. The rotation of shaft H is transmitted through gears l and Hi to side 8" of differential 8, and since 8 can now be considered as fixed, center 8", and shaft 9 upon which it is fixed will be rotated in accordance with the input at crank 10, but the direction of rotation will be such as to subtract the value of this input from the value of the input at crank i. The net rotation of shaft 9 will thus be equal to the director correction. Gear l1 mounted on shaft 9 rotates gear 58, shaft 19, and dial '29 at which the value of the director correction may be read opposite the index 2|. Shaft 9 through gears 22 and 23 also rotates side 24 of differential 24. The rotation of side 24'. since at this time side 24" can be considered as fixed against motion, causes the rotation of center 24" and shaft 25 upon which it is mounted.

The level angle and the speed of the roll are continuously determined from a suitable gyroscope 26 mounted by trunnions in a gimbal ring 2'! carried on trunnions 28 and 29 supported in suitable bearings fixed to the base on which the gyroscope is embodied. It will be understood that the trunnions of the gyroscope are maintained in the vertical plane of the line of sight by suitable training means. The relative motion between the ship and the gyroscope and its gimbal ring is transmitted through shaft 39, which is formed as an extension of the trunnion 29, to a contact arm 3i electrically insulated from shaft 39 by means of an insulation strip 32. A roller 33 is carried at the upper end of arm 3| and is connected to one side of an electrical supply 34 through a conductor 35. Roller 33 is adapted to contact with the under side of an arcuate commutator 35 which comprises an upper T-like portion 3? made of insulation material and lower metallic contacts 38 and 39. The vertical portion of the T extends between the contacts 38 and 39 and is of sufficient width to not only electrically separate them but also to keep roller 33 out of contact with these contacts when it is in the normal or central position. Contact members 38 and 39 are'connected through conductors 40 and 4| respectively to terminals of a reversing servo-motor 42. The common terminal of this motor is connected through conductor 43 to the second side of the electrical supply 34. Commutator 36 is carried by arms 44 which form offset extensions of worm gear sector 45 and is insulated therefrom by suitable insulation inserts. Worm gear sector 45 is carried by shaft 46 mounted for rotation in bearings 41 and 48, fixed relative to the trunnions for ring 21, and meshes with worm 49 carried by shaft 56 of the motor 42.

As the ship rolls gyroscope 26 and its gimbal ring 21 will move relative to the deck of the ship through an angle equal to the angle of roll and at a velocity equal to the velocity of roll. This motion is transmitted through shaft 3|] and arm 3| to roller 33 and carries it from its normal position on the insulation strip between contact members 38 and 39 to one or the other of these members, depending on the direction of roll, thereby closing the circuit of servo-motor 42 to cause it to rotate shaft and worm 49 in the direction corresponding to the direction of roll of the ship. Rotation of worm 49 will carry worm gear sector 45 and commutator 36 through an angle equal to that through which arm 3| has been carried, thus bringing the insulation strip 31 again into contact with roller 33 to open the circuit of the servo-motor. As the angular displacement of arm 3| is increased by movement of the gyroscope and its gimbal ring the cycle of operations is repeated. The follow-up system just described repeats accurately each increment of movement of the gyroscope and its gimbal ring as such movement occurs and produces a rotation of shaft 50 which although actually intermittent or variable is in effect continuous insofar as its effect upon the operation of the mechanism is concerned. The instantaneous value of the level angle may be read on dial 5| opposite index 52, dial 5| rotating with shaft 50 through gear 5|.

The instantaneous value of the level angle is transmitted by the rotation of shaft 50 through gears 53, 54, shaft 55, gears 56, 51, shaft 58 and gears 59. 60 to side 24" of differential 24. At this time side 24 may be considered as fixed against motion and the rotation of side 24" will cause a corresponding rotation of center 24" and shaft 25. The rotation of shaft 25 is in a direction relative to the rotations of the sides 24' and 24" so that the net rotation of shaft 25 is equal to the difference of the rotations of the sides. Shaft 25 carries gear 6| which rotates dial 62 to indicate opposite index 63 the instantaneous value of the difference between the director correction and the level angle.

At the end of shaft 25 is mounted a pinion 64 which transmits the rotation of shaft 25 to a gear wheel 65 fixed on shaft 66 to rotate this shaft in accordance with the instantaneous value of the difference between the director correction and the level angle. Shaft 66 projects through frame member 61 fastened to bed plate 68 of the switch mechanism and carries for rotation therewith a spider 69 and a fine control cam 10. The shape of cam I0 is in part that of a spiral. A double gear member comprising gears 1| and 12 having alike number of teeth but of-slightlydifferent pitch is mounted for rotation onone of the arms i spiden69. A weight 13 is carried on the other ann-tocounterbalance the Weight of the double gear. Gear "H of thedoublegear. meshes with a stationary gear i4 fixedto the frame members? by meansof a screw 55. Gear I2 of the double gear meshes witha gear 16- concentric with shaft GBand freelyrotatablethereon. Gear I6 i provided with a greater number of teeth than gear I4 and' rotates about shaft 66 when the doublegear 1!,12, walks around gear I4 due to the rotation of spider 09. Since the distance between the centers of the pair of gears II and I4 is the same as between the centers of the pair of gears .12 and I6, and since gear I6 has a greater numberof teeth than gear I4 it is necessary to make the diametrical pitch of gears 12 andIG slightly greater than of gears II and 74. The amount of rotation of gear 16 for each revolution of shaft 66 is equal tothe-number of teeth which gear I6 has in excesssof the number of teeth of gearlli divided by the number of teeth'of gear I6. Gear 16 is provided with a female threaded cylindricalextension which screws onto a male threaded cylindrical member forming an integral part of a coarse control cam ll. Cam TI is concentric with shaftfifi and freely rotatable thereon. The periphery of cam 71 is a true circle with the exception of an accurate notched portion I8 the length of which should not exceed the degrees of are through which cam TI moves during one revolution of cam '10.

Fine control cam I0 and coarse control cam TI contact with cam followers l0 and 80 respectively carried for rotation by a shaft 8% whose ends are fixed in follower arms 02 and 83. The follower arms are held in fixed spaced relation at their lower ends by a pint! and are fulcrumed on a shaft 85 fixed in frame members El and 86. A spring 8! connects pin 84 to an anchor 88 and forces thecam followers into contact with their respective cams. At the upper end of the follower arms are mounted insulation blocks 89 between which is mounted a metallic member 90 which carries the firing contact element 9!. Member 00 is slotted longitudinally and is provided with a screw .92 for fixing the firing contact element in any position of adjustment. A conductor 93 connects member 90 with one side of the firing circuit. Contact element 0| will move about shaft 85 as cam followers 79 and 80 follow cams 0 .and 11.

Contact arms 94 and 95 straddle the follower arms 82 and'83 and are pivoted at their lower ends on shaft fixed to frame members 6! and 86. Somewhat above the middle of the contact arms is mounted an insulation block 9! which carries a metallic member 98 having its upper portion cut away in the form of a semicircle to provide two arms. These arms are suitably perforated and act as bearings for the trunnions of a gimbal ring 09 in which is pivotally mounted the contact element I09. A conductor I 0| connects member 98 and contact element I00 to the firing circuit. Because of the form of suspension employed contact element I00 automatically adjusts itself to make a good contact with contact element BI in spite of the wear or adjustment of either of the contact elements.

Contact arms 94, 05 are fixed in spaced relation at their upper ends by a block I02 having a center bore I03 in which freely moves the end of pin I04. The other end of pin I04 takes the form of a screw I05 and is in screw threaded engagement with a frame member-I06. Ascompression spring IU'I encircIespinIM andabuts'atits ends against wear washers I08. Spring IIIIexerts a constant force in a-directiontending to keep block I02 in contact with a. cam I09 as best shown inFig. 3.

Cam I 09 which is fixed to a shaft I I0 is ofspiral form, it size-and characteristics being dependent upon the sizeand characteristicsofthe spiral portionsof fine control cam I0. shaft 0 eX'' tends through frame member 86 and has fixedto itsouter portion a bobbin dial II I suitably graduated to indicate the advance fire adjustment in minute ofrollopposite line -I I 2 on an index plate H3 which :fits betweenthe discs of the bobbin dial III. A screw 1 I1 terminating in a knurled head passesthrough a smooth hole in plate [I3 and is adapted to be screwed into a tapped hole in frame member to bring the index plate 3 into contact with the back disc of the bobbin dial I'Il to fix the dial, shaft H0 and cam I09 in any de-. sired position of adjustment. Pins IIE fastened to frame member 86-extend through holes in the index plate H3 and serve to keep it and line II2 fixed as an index markfor the graduated disc of the bobbin dial I I I. 1

Shaft I'I0 terminates at-its otherrendin a crank IIB which-is connected by'means'of a linkIIJ to the end IIBof a bell crank-lever IIS pivoted by means-ofpin I20, the support for which is .not shown. The other end of bellcrank II9=terminates in a finge -1H which fitsin an annular groove H2 in a collar I23. :Collar I23is slidably mounted on ashaft I24'and is pivotally connected to links I325 which are inturn pivotally connected to arms I26 carrying fixed at their lower ends balls I21. Arms I26 are pivoted at their upper ends in a collar I20 secured on shaft1i2 3. A compression spring surrounds shaft I24 and rests against collars I23and I26. A gear 129 mounted at the lower end of shaft i'fl meshes with gear 53 and transmits the rotation of shaft 50 to shaft I24. Arms I26 and balls I-2l will turn with shaft I24 and centrifugal force: acting on balls IZI will cause them to fly out and react against spring 128.

n The outward movement of balls I2! will carry collar I23 up and down-shaft I24 as thespeed of rotation of shaft I24varies. .The position of collar I23 on shaft 124 will at any time correspond to the velocity of roll of the ship. The movement of collar 23 istransmitted through bell crank II-9, link IIIand crank II6.to shaft IIO. Cam 109 is thereby rotatedto change the distance between shaft III! and block I02 to correspond with the velocity of roll at any instant. This will also move contact I00 away from its zero position, the po ition shown in Fig, 3, in proportion to the velocity of the roll.

Forithe purpose of explaining the manner .of operation of the switch we will assume that its parts are positioned-asshown in Fig. 2, andthat there is no roll. As the operator computes the value of the director correction by rotation of hand cranks I and has previously explained, shaft. 25 will rotate to cause a rotation offine and coarse cams l0 and H, as previously explained to position them in accordance with the computed value of the director correction. As cam 10 begins to rotate it will ofier an increasing radius to the contact of cam follower l9 and thus will carry it as well as follower arms Bland 83 and contact QI away from contact. I00. As the 10- tation continues cam-l0 will. finally offer its greatest radius to the contact of cam follower I9. The rotation of coarse cam i1 during this time will have carried notch 18 out of line with cam follower 80. With fine cam 10 in the position just mentioned cam follower 80 will be in contact with the periphery of coarse cam '11. From this point on coarse cam Tl will exercise control and will maintain contact 9| in the position shown in Fig. 3.

As the ship begins to'roll and the level angle and velocity of the roll are determined, as previously described, shaft 25 will rotate in accordance with the difference of the director correction value and the level angle and will rotate fine and coarse cams I and 11. As the level angle approaches to within a few degrees of the value of the director correction, notch 18 will be substantially in line with cam follower 80 so that fine cam 78 will again control the movement of cam follower T9, follower arms 82 and 83, and 7 contact 9|. As the ship rolls cam 189 will be moved, in the manner previously described, to

position contact me away from the position it occupies in Fig. 3 in proportion to the velocity of the roll. As the ship continues to roll the rotation of fine and coarse cams iii and 11 will continue with cam 10 offering a continuously diminishing radius to the contact of cam follower 19.

angular distance between this point on the periphery of cam Hi and the point at the minimum radius expressed in minutes of arc represents the angle of advance expressed in minutes of arc. From the previous description it is evident'that the angle of advance is alwaysproportional to the velocity of roll.

If it should become necessary or desirable, the described mechanism may be set to fire the guns for a period of time at a fixed angle of advance. This is accomplished by rotating bobbin dial HI until the desired value of the angle of advance is read opposite line M2 on brake plate H3 and then securing the dial in position by screwing screw H4 into frame member 86. By so doing shaft H8, cam 169, crank H6, link H1, bell crank I I9 and finger i2!) are fixed in position and prevent collar I23 and balls !21 from moving up and down shaft I24 as the velocity of the roll changes. The level angle solving mechanism will not be affected by thus fixing the position of cam I09 and will continue to function as previously described,

While a preferred embodiment has been shown and described, it is understood that the invention may be embodied in other forms, and various changes may be made without departing from its principle as defined in the appended claims.

We claim:

1. In a firing mechanism for a gun mounted on an angularly movable platform, the combination of a gyroscope mounted on the platform to measure the angular motion of the platform relative to a fixed datum, a firing switch, a computing mechanism for determining the angle of the platform relative to a horizontal datum with respect to which the gun is angularly set to be fired, a switch actuating means operatively connected to said computing mechanism adapted to be set to close the switch at the computed value of said angle, means operatively connecting said switch actuating means with the gyroscope, and

means operated by said gyroscope for advancin the closing of the switch in accordance with the velocity of the angular movement of the platform.

2. In a firing mechanism for a gun mounted on an angularly movable platform, the combination of a gyroscope mounted on said platform to measure the angular motion of the platform relative to a fixed datum, means controlled by the gyroscope for continuously determining the value of the angle which theplatform makes with the datum, independently operable calculating means for determining a particular angle of the platform relative to a horizontal datum with respect to which the guns are angularly set to be fired, a computing device operated by said last mentioned means and said gyroscope controlled means for combining the values of said angles, a firing switch, actuating means therefor operatively con nected to said computing device, whereby the switchwill beclosed when the two angles are equal, and means operated by the gyroscope for advancing the closing of the switch in proportion to the velocity of angular movement of the platform.

3. In a firing mechanism for a gun mounted on an angularly movable platform, the combination of a gyroscope mounted on said platform to measure the angular motion of the platform relative to a fixed datum, means controlled by the gyroscope for continuously determining the value of the angle which the platform makes with the datum, an independently operable computing device operated in accordance with firing data for computing a particular angle of the platform relative to a horizontal datum with respect to which the gun is angularly set to be fired, a second computing device operated by said first computing device and said gyroscope controlled angle determining means to compute the differenceof said angles, a firing switch, an actuating means therefor operated by said second computing device adapted to close said switch when the difference of said angles is zero, and means operated by the gyroscope to advance the closing of the switch in proportion to the velocity of angular movement of the platform,

4. In a firin mechanism for a gun mounted on an angularly movable platform, the combination 7 of a gyroscope mounted on the platform to measure the angular movement of the platform relative to a fixed datum, means controlled by the gyroscope for continuously determining the value of the angle which the platform makes with the datum, means independently operable in accordance with firing data for determining the particular angle of the platform relative to the datum at which the gun is to be fired, a differential having two input elements and an output element, one of the input elements being operatively connected to said first means and the other input element being operatively connected to said second means, a switch, actuating means therefor operatively connected to the output element of said differential and arranged to close the switch when the angle determined by the first means is equal to the angle determined by the second means, means for advancing the closing of the switch in proportion to the velocity of the angular movement of the platform, and means operatively connecting said last named means to the gyroscope.

5. In a firing mechanism for a gun mounted on an angularly movable platform, the combination of a gyroscope mounted on the platform to measure the angular movement of the platform relative to a: fixed datum, al'evel' angle determining means operated by said gyroscope; a director correction determining: means; means for combining said angles, a switch, means-actuated by said combining means adapted t0 close said switch when. the level angle equa'ls the director: correction, and means controll'edbysaid gyroscopeand adapted to advance the closingof the switch in accordancewithz the velocity of themovement-of the platform;

6.- In afiring'switch, a pair of relatively. movable ci'rcuit.closing;elements, one of said elements being movable to change the circuit closingsposition of said: elements, means for moving said one element, means for urgin the other: element of the pair into circuit closing relation with; said one element, andmeans for controlling the movement of said other element saidi control means including a painof correlated'rotatablecams, one ofsaid cams serving to'hold said other elementin a fixed position during a. plurality of revolutions of the. other of said cams.

'2. In a firing switch, a pair of relatively. movable: circuit closing contacts, a pair of spaced contact: arms-carrying. between them one of said contactsfor movementtherewith, means to move said arms to position said contact. as desired, a painof spaced follower arms carrying; between them. the other of: said contacts for movement therewith, means effective on. said follower arms for urging said; other. contact into circuit closing relation with said onescontact; a pair ofv followers mounted between said follower arms, a rotatable shaftaapair ofi'camsaconcentric therewith adapted to engage said followers, a speed reducing means connecting one of said cams with said shaft, the other of'said cams-being connected to shaft to rotate therewith, said-one cam bein adapted to restrain said other contact from movement while its periphery engages its respective cam follower, saidother cambeing adapted to enggeiits follower when saidiother cam is out of engagement with its followen-toallow saidi other contact to come into circuit closing relation with said one-contact.

8; In a firing switch, a.- paiirof relatively-movable circuit closing contacts, the:position of: one of said contacts determining, the; circuit; closin position of the contacts, azof contact-arms mounting said one contact between them, a cam follower member connecting said contact arms at their upper ends, means effective on said follower member for urging said one contact toward the other of said contacts, a rotatable shaft, a

cam mounted thereon adapted to engage said follower member to restrain its movement, means on said shaft for indicating the displacements of the follower member whereby said one contact may be definitely positioned by the rotation of said shaft, means to fix said shaft in any desired position, and means for controlling the movement of said other contact.

9. A firing switch comprising a pair of circuit closing elements individually mounted for separate movement, yielding means continuously urging one of the elements of the pair toward a circuit closing relation with the other element thereof, controlling means comprising a plurality of members operable to respectively exercise a fine and a coarse control of said one element and movable into mutual correlations in one of which the coarse controlling member maintains said one element separated from the other element, and in another correlation wherein the fine controlling member alone controls said one element "i0 and'with said yielding; means effects its displacement into said circuit closing relationwith the other element of the pair, and means.- to move said'other element of the pair to change the'circuit closing relation of said elements.

10. In apparatus for automatically operating a cont-acting device mounted on an angularly moving platform, the combination'of a pair ofrelatively movable members for controlling the device, a, gyroscope mounted on the platform to move relative thereto as the platform moves, a follow-upmechanism actuated in acordance with the relative movement of the said gyroscope, means connecting one of said members with the follow-up mechanism to control the movement ofsaid' member in accordance with the-relative movement of the gyroscope, means continuously operated by said follow-up mechanism in response to the instantaneous velocity: of the-relative movement of theigyroscope, and'meanscontinuously operated: byv said velocity responsive means to position.thesecondmember of thepair so as to variably advance the operation of the contacting device as:a functionof the'instantaneous velocity of;the relative movement' of the gyroscope.

11. In a firing mechanism for a gun mounted on an angularly movableplatform, thecombination of a gyroscope, mounted on the platform:to measurethe' angular motion of the-platform relative to a fixed datum, a firingswitch, means=to set the switch to close at a desired position of the platform relative to-the datum, means: actuated bythe gyroscopetto operate the switch when the platform attains. the desired position; speed responsive means continuously operated by the gyroscope, and means continuousl actuated by the speed-responsive. means tovariably advance the closing of the switch in' proportion-.130 the "instantaneous speedof theangular movement-of the, platform.

12. In a firingcmeohanism for-a gun mounted on an angularly movable platform; the combination of a gyroscope mounted on the platform to measure the angular motion of the platform relative to afixed datum, afiring switch, aswitch actuating mechanism, means to set'said mechanism in accordance. withthe angle of the plat f-orm relative to the datum at which it desired to.'operate the switch; meanscontinuously connecting said mechanism to the gyroscope to operate said mechanism in accordance with the movement of the platform relative to the datum, velocity responsive means continuously operated by the yroscope and means connecting the velocity responsive means to the switch for variably advancing the closing of the switch in proportion to the instantaneous velocity of angular movement of the platform.

13. In a firing mechanism for a gun mounted on an :angularly movable platform, the combination of a gyroscope mounted on the platform to measure the angular movement of the platform relative to a fixed datum, a, level angle responsive means operated by said gyroscope, a director correction angle setting means, differential means operably connected to compare said last two means, a switch, means actuated by said diiferential means adapted to close said switch when the level angle equals the director correction angle, and means continuously actuated by the gyroscope to variably advance the closing of the switch as a function of the instantaneous rate of measured angular movement of the platform.

14. In a firing mechanism for a gun mounted on an angularly movable platform, the combination of a, fixed datum establishing means co-acting with the platform to continuously position a member in accordance with the angular motion of the platform relative to the datum, a firing switch, means settable to represent an angular position of the platform relative to the datum at which it is desired to close the switch, means differentially actuated by the member and the settable means to operate the switch when the platform attains the desired position, a device operatively connected with the member and continuously responsive to the instantaneous speed of the angular movement of the platform, and means operatively connecting the speed responsive device to the switch to variably advance the closing point of the switch as a function of said speed.

15. In a firing mechanism for a gun mounted on an angularly movable platform, the combination of an element, controlling means operably connected to the element for moving the element relatively to the platform reversely to the angular movement of the platform and in proportion thereto, whereby the movement of the element measures the angular, motion of the platform relative to a fixed datum, a firing switch, means to set the switch to close at a certain position of the platform, means actuated in accordance with the movement of the said controlling means in positioning the element to close the switch when the platform attains the certain position, a device continuously responsive to the instantaneous speed of the angular movement of the platform, and means operatively connecting the speed responsive device to the switch adapted to effect the closing of the switch in advance of the platform attaining the certain position.

16. In a, firing mechanism for a, gun mounted on an angularly movable platform, the combination of a fixed datum establishing means co-acting with the platform to continuously position a member in accordance with the angular motion of the platform relative to the datum, a firing switch, a switch actuating mechanism, means effective to set said mechanism in accordance with the angle of the platform relative to the datum at which it is desired to close the switch, means operatively connecting said mechanism to said member to thereby operate said mechanism in accordance with the movement of the platform relative to the datum, and speed'measuring means continuously operated by the datum establishing means for advancing the closing of the switch in proportion to the instantaneous velocity of angular movement of the platform as represented by movement of the member.

17. In a firing mechanism for a gun mounted on an angularly movable platform, the combination of a firing switch, a member continuously positioned in accordance with the angular movement of the platform, means actuated by said member for closing said switch at a certain angular position attained by the platform during its angular movement, a centrifugal device continuously operable by the member in response to the instantaneous velocity of the angular movement of the platform, and means operatively connecting the velocity response device to the switch to effect a closure thereof in advance of the platform attaining said certain angular position.

18. Automatic means for firing a gun, comprising a gyroscope, a pair of circuit closing contacts, power means controlled by said gyroscope to move'one of said contacts toward the circuit closing position according to the angular position of a body upon which said gyroscope is mounted, and means continuously operated by said power means and-responsive to the instantaneous velocity of the power means to variably adjust the circuit closing position of the other of said contacts in accordance with the said instantaneous velocity.

ELLIOTT P. ROSS. HARRY S. MARSH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 626,002 Cuadros May 30, 1899 678,757 Obry July 16, 1901 1,360,694 -Sperry Nov. 30, 1920 1,384,005 Akemann Jul 5, 1921 1,492,728 Hunt May 6, 1924 1,507,209 Schneider Sept. 2, 1924 1,575,606 I Henderson Mar. 2, 1926 

